1. Technical Field
The description relates to a DC/DC boost converter, and more particularly, to a DC/DC boost converter having alternate boost driving mechanism.
2. Description of the Related Art
Along with a demand of providing different DC voltages for use in a variety of components installed in complicated electronic apparatuses, such as liquid crystal displays or computer hosts, a DC/DC boost converter disposed therein is required to boost a DC voltage generated by a power supply so as to provide a higher DC voltage for driving part of the components to function properly. FIG. 1 is a circuit diagram schematically showing a prior-art DC/DC boost converter based on single-phase operation mechanism. As shown in FIG. 1, the DC/DC boost converter 100 includes an inductor 110, a power switch 120, a power diode 130, and an output capacitor 180. The DC/DC boost converter 100 is employed to perform a DC voltage boost operation on an input voltage Vin for generating an output voltage Vout furnished to a load 190. In the single-phase boost operation of the DC/DC boost converter 100, the power switch 120 is required to perform a high-frequency operation of periodically switching turn-on/turn-off states according to a control signal Sctr, for controlling the energy-storing/energy-releasing operations of the inductor 110. And the energy-releasing operation of the inductor 110 is employed to charge the output capacitor 180 via the power diode 130, thereby generating the output voltage Vout. That is, in the aforementioned single-phase boost operation, the energy-storing operation of the inductor 110 is performed by a current flowing through the power switch 120, and the charging operation of the output capacitor 180 is performed by a current flowing through the inductor 110 and the power diode 130. In view of that, the power switch 120, the inductor 110 and the power diode 130 are all required to have high current/voltage rating for tolerating high working current/voltage, which leads to high production cost. Besides, high capacitance of the output capacitor 180 is required to reduce the ripple of the output voltage Vout. Further, serious electromagnetic interference (EMI) is likely to occur because of high ripple current flowing through the inductor 110, which causes significant electromagnetic energy loss and thus reduces energy conversion efficiency. Finally, the high-frequency on/off switching operation of the power switch 120 may deteriorate the lifetime thereof.